A simple implementation of manipulating JSON objects in Javascript and adding, deleting, and modifying

<script type="text/javascript">
  var jsonObj2 = { teacher: [
    { name: "jordan", sex: "m", age: "40" },
    { name: "bryant", sex: "m", age: "28" },
    { name: "McGrady", sex: "m", age: "27" }
  ]};

  var jsonObj2New = {};
  $("#btn").click(function () {
    //invoke the update
    updateData("jordan");
    var persons = jsonObj2.teacher;
    for (var i = 0; i < persons.length; i++) {
      var cur_person = persons[i];
      alert(cur_person.sex);
    }

    //invoke the delete
    deleteData("jordan");
    var persons = jsonObj2.teacher;
    for (var i = 0; i < persons.length; i++) {
      var cur_person = persons[i];
      alert(cur_person.sex);
    }

    //push 
    var temp = { name: "kenny", sex: "m", age: "25" };
    jsonObj2.teacher.push(temp);

    var persons = jsonObj2.teacher;
    for (var i = 0; i < persons.length; i++) {
      var cur_person = persons[i];
      alert(cur_person.name);
    }

  });

  function updateData(name) {
    var persons = jsonObj2.teacher;
    //alert(name);
    for (var i = 0; i < persons.length; i++) {
      var cur_person = persons[i];
      if (cur_person.name == name) {
        persons[i].sex = "f";
      }
    }
  }

  function deleteData(name) {
    var persons = jsonObj2.teacher;
    //alert(name);
    for (var i = 0; i < persons.length; i++) {
      var cur_person = persons[i];
      if (cur_person.name == name) {
        jsonObj2.teacher.splice(i, 1);
      }
    }
  }
  </script>